Thawban, the freed slave of the Messenger of Allah (ﷺ), narrated that:When he finished the prayer, the Messenger of Allah (ﷺ) would pray for forgiveness three times and say: 'Allahumma anta asalam, wa minka as-salam tabarakta ya dhal-jalali wal-ikram (O Allah, You are the source of eace (or the One free from all faults) and from You comes peace, blessed are You, O Possessor of Majesty and Honor

English translation · Sunan an-Nasa'i